Implemented lightweight primitive iterators/streams type adapters

src/main/java/lsh/ext/gson/StreamedTypeAdapter.java

@@ -0,0 +1,44 @@
+package lsh.ext.gson;
+
+import java.util.function.BiConsumer;
+import java.util.function.Function;
+import java.util.function.Predicate;
+
+import com.google.gson.TypeAdapter;
+import com.google.gson.stream.JsonReader;
+import com.google.gson.stream.JsonWriter;
+import lombok.AccessLevel;
+import lombok.RequiredArgsConstructor;
+
+@RequiredArgsConstructor(access = AccessLevel.PROTECTED)
+public final class StreamedTypeAdapter<S, I>
+		extends TypeAdapter<S> {
+
+	private final Function<? super JsonReader, ? extends S> toStream;
+	private final Function<? super S, ? extends I> toIterator;
+	private final Predicate<? super I> hasNext;
+	private final BiConsumer<? super JsonWriter, ? super I> writeNext;
+
+	public static <S, I> TypeAdapter<S> getInstance(
+			final Function<? super JsonReader, ? extends S> toStream,
+			final Function<? super S, ? extends I> toIterator,
+			final Predicate<? super I> hasNext,
+			final BiConsumer<? super JsonWriter, ? super I> writeNext
+	) {
+		return new StreamedTypeAdapter<>(toStream, toIterator, hasNext, writeNext);
+	}
+
+	@Override
+	public void write(final JsonWriter out, final S cursor) {
+		final I iterator = toIterator.apply(cursor);
+		while ( hasNext.test(iterator) ) {
+			writeNext.accept(out, iterator);
+		}
+	}
+
+	@Override
+	public S read(final JsonReader in) {
+		return toStream.apply(in);
+	}
+
+}

src/main/java/lsh/ext/gson/ext/java/util/stream/StreamTypeAdapter.java

@@ -1,15 +1,21 @@
 package lsh.ext.gson.ext.java.util.stream;
 
 import java.io.IOException;
+import java.util.PrimitiveIterator;
 import java.util.Spliterator;
 import java.util.Spliterators;
 import java.util.stream.BaseStream;
+import java.util.stream.DoubleStream;
+import java.util.stream.IntStream;
+import java.util.stream.LongStream;
 import java.util.stream.Stream;
 import java.util.stream.StreamSupport;
 
 import com.google.gson.TypeAdapter;
 import lombok.experimental.UtilityClass;
 import lsh.ext.gson.JsonArrayStreamTypeAdapter;
+import lsh.ext.gson.JsonReaders;
+import lsh.ext.gson.StreamedTypeAdapter;
 
 @UtilityClass
 public final class StreamTypeAdapter {
@@ -31,4 +37,43 @@ public static <E> TypeAdapter<Stream<E>> forStream(final TypeAdapter<E> elementT
 		}, BaseStream::iterator);
 	}
 
+	public static final TypeAdapter<DoubleStream> forDoubleStream = StreamedTypeAdapter.getInstance(
+			in -> StreamSupport.doubleStream(Spliterators.spliteratorUnknownSize(JsonReaders.asDoubleIterator(in), Spliterator.IMMUTABLE), false),
+			DoubleStream::iterator,
+			PrimitiveIterator.OfDouble::hasNext,
+			(out, iterator) -> {
+				try {
+					out.value(iterator.next());
+				} catch ( final IOException ex ) {
+					throw new RuntimeException(ex);
+				}
+			}
+	);
+
+	public static final TypeAdapter<IntStream> forIntStream = StreamedTypeAdapter.getInstance(
+			in -> StreamSupport.intStream(Spliterators.spliteratorUnknownSize(JsonReaders.asIntIterator(in), Spliterator.IMMUTABLE), false),
+			IntStream::iterator,
+			PrimitiveIterator.OfInt::hasNext,
+			(out, iterator) -> {
+				try {
+					out.value(iterator.next());
+				} catch ( final IOException ex ) {
+					throw new RuntimeException(ex);
+				}
+			}
+	);
+
+	public static final TypeAdapter<LongStream> forLongStream = StreamedTypeAdapter.getInstance(
+			in -> StreamSupport.longStream(Spliterators.spliteratorUnknownSize(JsonReaders.asLongIterator(in), Spliterator.IMMUTABLE), false),
+			LongStream::iterator,
+			PrimitiveIterator.OfLong::hasNext,
+			(out, iterator) -> {
+				try {
+					out.value(iterator.next());
+				} catch ( final IOException ex ) {
+					throw new RuntimeException(ex);
+				}
+			}
+	);
+
 }

src/main/java/lsh/ext/gson/ext/java/util/stream/StreamTypeAdapterFactory.java

@@ -16,19 +16,19 @@ public static <E> ITypeAdapterFactory<Stream<E>> forStream(final boolean useBegi
 		return ITypeAdapterFactory.forClass(Stream.class, typeResolver -> StreamTypeAdapter.forStream(typeResolver.getTypeAdapter(0), useBeginEnd, autoClose));
 	}
 
-	public static ITypeAdapterFactory<DoubleStream> defaultForDoubleStream = forDoubleStream(DoubleStreamTypeAdapter.getInstance());
+	public static ITypeAdapterFactory<DoubleStream> defaultForDoubleStream = forDoubleStream(StreamTypeAdapter.forDoubleStream);
 
 	public static ITypeAdapterFactory<DoubleStream> forDoubleStream(final TypeAdapter<DoubleStream> typeAdapter) {
 		return ITypeAdapterFactory.forClass(DoubleStream.class, typeResolver -> typeAdapter);
 	}
 
-	public static ITypeAdapterFactory<IntStream> defaultForIntStream = forIntStream(IntStreamTypeAdapter.getInstance());
+	public static ITypeAdapterFactory<IntStream> defaultForIntStream = forIntStream(StreamTypeAdapter.forIntStream);
 
 	public static ITypeAdapterFactory<IntStream> forIntStream(final TypeAdapter<IntStream> typeAdapter) {
 		return ITypeAdapterFactory.forClass(IntStream.class, typeResolver -> typeAdapter);
 	}
 
-	public static ITypeAdapterFactory<LongStream> defaultForLongStream = forLongStream(LongStreamTypeAdapter.getInstance());
+	public static ITypeAdapterFactory<LongStream> defaultForLongStream = forLongStream(StreamTypeAdapter.forLongStream);
 
 	public static ITypeAdapterFactory<LongStream> forLongStream(final TypeAdapter<LongStream> typeAdapter) {
 		return ITypeAdapterFactory.forClass(LongStream.class, typeResolver -> typeAdapter);

src/test/java/lsh/ext/gson/ext/java/util/stream/DoubleStreamTypeAdapterTest.java

@@ -21,7 +21,7 @@ protected List<?> normalize(@Nullable final DoubleStream value) {
 	protected List<Arguments> makeTestCases() {
 		return List.of(
 				makeTestCase(
-						DoubleStreamTypeAdapter.getInstance(),
+						StreamTypeAdapter.forDoubleStream,
 						"[1,2,4,8]",
 						"[1.0,2.0,4.0,8.0]",
 						Stream.of(1.0D, 2.0D, 4.0D, 8.0D).mapToDouble(value -> value)

src/test/java/lsh/ext/gson/ext/java/util/stream/IntStreamTypeAdapterTest.java

@@ -21,7 +21,7 @@ protected List<?> normalize(@Nullable final IntStream value) {
 	protected List<Arguments> makeTestCases() {
 		return List.of(
 				makeTestCase(
-						IntStreamTypeAdapter.getInstance(),
+						StreamTypeAdapter.forIntStream,
 						"[1,2,4,8]",
 						Stream.of(1, 2, 4, 8).mapToInt(value -> value)
 				)

src/test/java/lsh/ext/gson/ext/java/util/stream/LongStreamTypeAdapterTest.java

@@ -21,7 +21,7 @@ protected List<?> normalize(@Nullable final LongStream value) {
 	protected List<Arguments> makeTestCases() {
 		return List.of(
 				makeTestCase(
-						LongStreamTypeAdapter.getInstance(),
+						StreamTypeAdapter.forLongStream,
 						"[1,2,4,8]",
 						Stream.of(1L, 2L, 4L, 8L).mapToLong(value -> value)
 				)